This report presents the results of a joint Bureau of Mines-U.S. Department of Energy project that evaluated a newly developed low- coal mining system: the 4m miniminer system. The evaluation took place from April through October 1981 and determined potential health, safety, and productivity factors for the mining system using the surface test facilities at Bruceton, Pennsylvania. The planning, testing, results of testing, and a summary evaluation of the 4m miniminer system are included in the report. The miniminer system was found to be a very good concept with future potential for safe, healthful, and economic production in thin-seam mining. The mining system was also judged to have considerable potential for use in some coal seams that are presently considered unminable by other existing mining equipment. The preproduction, prototype version of the miniminer system that was tested suffered from several safety and production problems. These problems are also described, along with suggested remedies.